1. Field of the Invention:
This invention relates to a stabilized synthetic resin composition. More particularly, it relates to a stabilized synthetic resin composition comprising piperidyl ester(s) of an aliphatic monocarboxylic acid and polypiperidine compound(s).
2. Description of the Prior Art:
It has been known that synthetic resins including polyethylene, polypropylene, ABS and polyvinyl chloride resins are sensitive to ultraviolet light and that ultraviolet light would cause, for example, coloration or a decrease in the mechanical strengths of these resins, which makes the prolonged utilization of the same impossible.
Compounds which have been employed to prevent these troubles include benzophenones, benzotriazoles, benzoates and hindered amines. Recently hindered amines represented by polyalkylpiperidine compounds, among the abovementioned compounds, have attracted public attention, since they cause no coloration of resins and show relatively high photostabilizing effects.
Although hindered amines represented by piperidine compounds are relatively excellent as phostostabilizers, each of these compounds shows only limited effects when employed alone. Therefore it has been proposed to use a piperidine compound together with, for example, benzophenone, benzotriazole, phenyl salicylate or oxalic diamide ultraviolet absorbers. However the effect of the combined use of these materials is only additive so that it is unsatisfactory from a practical viewpoint.
Japanese Patent Laid-Open No. 79033/1983 has proposed addition of a stabilizer, which comprises a specific combination of a piperidine compound having a relatively low molecular weight and one having a relatively high molecular weight, to an organic polymer. However the effect thus obtained is likewise additive and thus considerably unsatisfactory in practice.